Arrangement for electromagnetically setting drum series print wheels

ABSTRACT

A printing device, e.g., for a calculator having a row of print wheels located in relative positions by a series of pawls which in turn are actuated by electromagnetic coils through stems which are shaped to such angles at their pawl engaging ends that the coils can occupy a wider space than the wheels and pawls.

United States Patent [1 1 Gross et a].

[451 Apr. 24, 1973 ARRANGEMENT FOR ELECTROMAGNETICALL Y SETTING DRUMSERIES PRINT WHEELS Inventors: Henry Gross; Samuel Gross, both ofLondon, England Gross Cash Registers Limited, London, England Filed:July 8, 1971 Appl. No.: 160,714

Assignee:

Foreign Application Priority Data July 18, 1970 Great Britain..34,929/70 U.S. Cl. ..10l/99, 335/262, 335/267, 335/268 Int. Cl ..B41j45/00, B4lj l/6O Field of Search ..lOl/93 C, 99, l 10, 101/96, 97, 98,95; 197/]; 335/262, 263,

References Cited UNITED STATES PATENTS 4/1957 Shepard ..101/93 C 6/1965Foley ct al. 101/399 X 8/1966 Peters 1 197/53 12/1966 Wasserman ...101/93 x 3/1967 Hickerson ..l97/ l 8 H1969 Bakardjiev et a1 ..l01/99 X 31970 Potter et al. ...101/93 c 6/1971 Guzak ...lOl/93 C 2/1971. DePuy etal. ..lO1/93C Primary Examiner-William B. Penn Attorney-Alexander &Dowell ABSTRACT A printing device, e.g., for a calculator having a rowof print wheels located in relative positions by a series of pawls whichin turn are actuated by electromagnetic coils through stems which areshaped to such angles at their pawl engaging ends that the coils canoccupy a wider space than the wheels and pawls.

6 Claims, 2 Drawing Figures ARRANGEMENT FOR ELECTROMAGNETICALLY SETTINGDRUM SERIES PRINT WHEELS This invention relates to printing devices forcash registers, computing weighing machines and other machinesespecially those in which the data is transmitted to the printingdevices by electric pulses.

In order to arrange an adequate number of printing wheels in acomparatively small width, the wheels are made somewhat thin and notmuch more than is required by the size of the print type on theperipheral surface of the wheels. These may carry ratchet teeth inaccordance with the invention described in our copending British Pat.application Ser. No. 34,928/70 filed coincidentally herewith or they maybe connected with separate ratchet means of the same thickness. Pawlsare required to engage the ratchet means to locate them in requiredpositions and the pawls are operated by solenoids. However, solenoids ofequally small size are expensive to make and require unduly largevoltage and current.

According to the present invention we provide a printing device having anumber of printing wheels side by side, pawls and ratchets associatedwith the printing wheels for stopping the wheels in required positions,electromagnetic devices including coils, for operating the pawls, saidcoils being of greater width than the printing wheels and arranged in atleast two lines parallel to each other, each having a stem fortransferring motion from the electromagnetic device to a pawl, the stemshaving their pawl engaging ends lying between two planes which areparallel to each other and close together, the pawl engaging ends of atleast most of the stems being angled so that the pawl engaging tips ofthe stems are all spaced apart from each other along the double row andthe double row is about the same length as that occupied by the pawlsand ratchet means and printing wheels and less than that of the doublerow of coils.

The invention is illustrated by way of example in the accompanyingdiagrammatic drawing wherein:

FIG. 1 is a perspective view of a part of a device made in accordancewith the invention; and

FIG. 2 is an end view thereof.

The printing device comprises a row of printing wheels (FIG. 2) havingratchet teeth 11 and printing characters 12. These wheels are mounted ona common spindle and each has a spring 13 to urge it in theanticlockwise direction of FIG. 2. A rod 15 extends through slots 16 inthe wheels and can be moved to release the. wheels so that they rotateunder the int fluence of the springs 13 until they are arrested by pawls19 one of which is provided for each wheel. The pawls l9 and wheels thusextend in a row. The rod 15 is operated by pinion l4, toothed segment17, and cam 18.

The pawls are two armed and are actuated to their printing wheelstopping positions by the action of solenoid coils 20. The solenoids aremounted in brackets 21 which are carried by a mounting plate 22 by bolts23 which also carry a guide plate 24. The mounting plate is in turnmounted on a base plate 26 which forms part of a frame 27. The frame '27carries a top guide plate 28.

The solenoids have movable armatures 30 connected by cross-strips orpins 31 to stems arranged in two rows, 32 33 parallel to each other andguided in slots in the guide plates 24, 28. The pins 31 can move upthrough slots in the plate 24.

The solenoid coils 20 are in two rows parallel to each other and theiraxes are all parallel to each other. In this example each row consistsof eight solenoids. Each solenoid may have a diameter of about half aninch so that the double row is about 4 inches long. They are required tooperate the pawls which (and the wheels) are about 3 inches overallwidth or even less.

Above the guide plate 28 the upper ends of the stems 32, 33 are shapedto converge to the required smaller length but with all the upper tipsthat contact the pawls spaced apart from each other lengthwise of thedouble row. The ends of the stems to the left of the central plane ofthe device are a mirror image of the ends to the right of the centralplane. The upper ends of the two rows of stems lie between two closelyspaced planes indicated by the arrows 36 and in fact the extreme tipsmay (as shown) be bent into line with each other, i.e., so as to liebetween two very closely spaced planes Indicated by the arrOws 37.

The ends or tipS of the stems are together about the same length as thewidth occupied by the pawls with the ratchet teeth and the printingwheels and less than that of the double row of solenOid coils. The stemsare between the double row of coils and extend above and below thecoils.

The ends of the solenoid coils may be connected to a printed circuit(not shown) attached by a push-on connector to the output of acalculator circuit.

If desired the solenoids may be replaced by electromagnetic deviceshaving armatures fixed in their coils and operating by magneticattraction directly on the ends of the stems.

The device includes members 40 for pressing paper 41 against the row ofprinting characters. An inking ribbon (not shown) will also be provided.

What we claim is:

l. A printing device having a number of printing wheels side by side,said wheels having ratchet teeth thereon, pawls engageable with saidratchet teeth for stopping the wheels in required positions, said pawlshaving an axial overall dimension approximately the same as that of theprinting wheels, electromagnetic devices including a set of coils andmovable armatures for operating the pawls, said set of coils being ofgreater combined width than the combined width'of the printing wheels,said coils being arranged in at least two rows, the two rows lying intwo planes which are parallel to each other, the coils all beingparallel to each other, each electromagnetic device having associatedtherewith a stem arranged for transferring motion from the armature ofthe electromagnetic device to one of said pawls, each stem having a pawlengaging end, the stems lying in two rows located between the two rowsof coils, the stems having their pawl engaging ends lying between twoplanes which are parallel to each other and close together, the stemsacting on the pawls respectively to move the pawls into engagement withthe ratchet teeth, the pawl engaging ends of at least most of the stemsbeing angled in relation to the main parts of the stems in the directionto reduce the length of the row of tips of the pawl engaging ends to alength which is less than the width of the double row of the main partsof the stems and of the set of coils axially of the printing wheels andsuch that the pawl engaging tips of the stems are all spaced apart fromeach other along the double row of coils to engage the pawls and thedouble row length occupied by all the tips is about the same length andthe width axially of the printing wheels occupied by the pawls andprinting wheels.

2. A printing device as claimed in claim 1 wherein the stems projectbeyond the coils at both ends, the stems at one end being connected tothe adjacent ends of the armatures of the electromagnetic devices andthe other ends of the stems engaging the pawls.

3. A printing device as claimed in claim 2, having a plate to which areattached the ends of the coils near

1. A printing device having a number of printing wheels side by side,said wheels having ratchet teeth thereon, pawls engageable with saidratchet teeth for stopping the wheels in required positions, said pawlshaving an axial overall dimension approximately the same as that of theprinting wheels, electromagnetic devices including a set of coils andmovable armatures for operating the pawls, said set of coils being ofgreater combined width than the combined width of the printing wheels,said coils being arranged in at least two rows, the two rows lying intwo planes which are parallel to each other, the coils all beingparallel to each other, each electromagnetic device having associatedtherewith a stem arranged for transferring motion from the armature ofthe electromagnetic device to one of said pawls, each stem having a pawlengaging end, the stems lying in two rows located between the two rowsof coils, the stems having their pawl engaging ends lying between twoplanes which are parallel to each other and close together, the stemsacting on the pawls respectively to move the pawls into engagement withthe ratchet teeth, the pawl engaging ends of at least most of the stemsbeing angled in relation to the main parts of the stems in the directionto reduce the length of the row of tips of the pawl engaging ends to alength which is less than the width of the double row of the main partsof the stems and of the set of coils axially of the printing wheels andsuch that the pawl engaging tips of the stems are all spaced apart fromeach other along the double row of coils to engage the pawls and thedouble row length occupied by all the tips is about the same length andthe width axially of the printing wheels occupied by the pawls andprinting wheels.
 2. A printing device as claimed in claim 1 wherein thestems project beyond the coils at both ends, the stems at one end beingconnected to the adjacent ends of the armatures of the electromagneticdevices and the other ends of the stems engaging the pawls.
 3. Aprinting device as claimed in claim 2, having a plate to which areattached the ends of the coils near the pawls, and said plate isprovided with openings through which the stems project so as to beguided thereby.
 4. A printing device as claimed in claim 1, wherein theelectromagnetic devices are solenoids having circular coils.
 5. Aprinting device as claimed in claim 1, wherein the electromagneticdevices have fixed poles adapted to operate the stems by magneticattraction.
 6. A printing device as claimed in claim 1, wherein the pawlengaging tips of all the stems are in line with each other.